Patent Literature 1 discloses a vehicle door latch device wherein a latch capable of engaging with a striker and a ratchet capable of engaging with the latch are disposed in an engagement mechanism housing having a striker entering groove, and a drain passage is provided at a lower edge of the engagement mechanism housing, thereby a rain water invading into the engagement mechanism housing from the striker entering groove is discharged to the outside through the drain passage without staying, and it becomes possible to maintain good operation of the latch and the ratchet as there is no risk of rain water freezing at low temperature.
Patent Literature 2 discloses a vehicle door latch device which comprises a latch capable of engaging with a striker, a ratchet capable of engaging with the latch, an opening lever causing the ratchet to perform a releasing operation, and a crash releasing prevention mechanism disposed lower than the ratchet and preventing an opening of a door by preventing a rotation of the ratchet when the opening lever rotates at an excessive speed due to a crash accident or the like. The crash releasing prevention mechanism is constituted by movable elements that influence the operation of the ratchet.